The invention relates to a shock absorber for the absorption of vibrations acting horizontally between the foundation and the base of an apparatus such as high-voltage switch-gear to be installed in earthquake-prone areas. The shock absorber includes a first component which can be firmly anchored in a foundation and a second component which is movable horizontally relative to the first component and can be firmly coupled to the base. Also provided is means for attenuating the vibrations between both shock absorber components.
When installing high-voltage switch-gear such as outdoor power circuit breakers in earthquake-prone areas, the problem often arises to keep horizontally acting vibrations occurring during earthquake shocks away from the base of the apparatus in order to avoid damage to the switch-gear.
Commercially available rubber spring elements, so-called anti-vibration mounts, suitable as supports for smaller machines, are not suited as shock absorbers for high-voltage switch-gear, which may weigh several thousand kilograms, because their ability to function is largely lost by the supported weight; that is, the damping components of the anti-vibration mounts are already deformed by the load of the switch-gear to the point where they behave like stiff, rigid parts.
German Pat. No. 335,259 discloses a foundation for large prime movers with reciprocating or rotating machine masses. The foundation is so constructed that vibrations emanating from the machine masses are not transferred to the foundation. To accomplish this, the known foundation is provided with a foundation block resting on roller bearings and supported on piers via additional buffers, such as hydraulic buffers with air cushions. This results in a damping device with a first, upper component which can be connected to the apparatus and a second, lower component which can be anchored to the foundation, both components of the damping device being supported by roller bearings for the achievement of any mutual horizontal motion. Centering damper elements are disposed between the upper and lower component.
Deutsche Auslegeschrift No. 1,182,604 discloses an arrangement for attenuating vibrations in drum type washing machines with a spin cycle in which are provided, both at the base plate and at the upper part of the machine, rollers enabling the machine to have horizontal mobility. In addition, brake linings are provided between the base plate and the upper part of the machine causing a reduction of the horizontal motion energy.
Finally, it is known from U.S. Pat. No. 3,730,463 to equip a shock absorber for switch-gear to be installed in earthquake-prone areas with balls for a horizontal motion and with an annular rubber part as a damping element which centers the two components of the shock absorber.